In the present study, we used a cuasi-experimental design to evaluate the impact of changing the organization of preschool centres in children’s self regulation and socio-emotional development. The changes included giving the children the opportunity to choose activities, the conformation of multi-aged groups during part of the day, and promoting a higher commitment of educators to specific aspects of the curriculum. Our results show that children in the intervention group display improved self-regulation, particularly in a decrease in negative affectivity, conduct problems and emotional symptoms. Additionally, they showed increase complexity in their play behaviours and more peer-interactions in social play. The intervention proved to be a low-cost, easy to implement alternative with promising results in a country with restricted financial resources in education.